1. Field of the Invention
This invention relates to text editing with the aid of a CRT. More particularly it relates to a technique for reducing and displaying a representation of a full page of text on less than the entire screen. 2. Description of the Prior Art
In word processing systems with a display for displaying text as it is entered and edited, an operator is usually unable to display an entire page because of the size of the screen. Often times, however, seeing the full page is desirable as it enables the operator to appreciate the proper spatial relationship of the text to the page boundaries.
One prior art technique for solving this problem is described in U.S. Pat. No. 4,168,489 wherein the actual text characters are compressed for the miniature format display. The height of each character is reduced by utilizing only certain of the rows of vertical dots. Horizontal reduction is accomplished by means of a circuit which decreases the current flowing through the horizontal winding of the cathode ray tube deflection yoke. The lessened current compresses the image width on the visual display screen. That patent also discusses other prior art techniques for reducing a page of text to fit within the confines of a partial page word processing system and points out why they are inappropriate. This reference teaches reduction of a page to about one-third its size so as to effectively fill the viewing area of the display. That is, a full page of text is displayed using characters reduced in both the horizontal and vertical dimensions of two-thirds. Not all of the compressed characters are legible. Normal word processing functions can be performed, however.
Another approach can be found in IBM Technical Disclosure Bulletin "Abbreviated Character Font Display", Volume 19, No. 9, February 1977, page 3248. That author discloses a technique for displaying significant shapes of characters, words and phrases to allow an operator the ability to quickly access a particular portion of the page without actually reading displayed text.
A different approach is illustrated in IBM Technical Disclosure Bulletin article "Combination of Alphanumeric and Formatting Data on the CRT Display", Volume 15, No. 7, December 1972, page 2136. A single dot is used to represent each normally 5.times.7 dot character. In this technique, the operator can see several lines of text in normal size as well as the total unit of text as represented by dots only. The active window area of the dot only portion of the display is intensified so that the operator can perceive the format relationship of the active text to the entire text. This active window may be moved at the operator's discretion. Interactivity is not disclosed in this article. Nor is there any attempt to make the displayed text representation proportional to hard copy page size, print pitch or orientation.
U.S. Pat. No. 4,107,664 relates to raster scanned display systems in which character size is enlarged in the horizontal dimension by increasing the number of times each dot is sequentially displayed.